Madrigal Imaging Audio/Video Preamplifier manual Save Your Changes if ANY by Pressing Enter

Phantom Center Channel

Physical Setup

Testing For Proper Phasing

If your system does not include a center channel speaker, choose “none.” Doing so will place the PAV into a “phantom” center channel mode wherein the information which would normally be directed to the center speaker by the Pro Logic circuitry will instead be sent equally to both left and right speakers. This process creates an illusion of a center channel speaker for those sitting on the centerline between Left and Right speakers. (Having a real center channel makes seating arrangements far more flexible than is the case with only a “phantom” center.)

4.SAVE YOUR CHANGES (IF ANY) BY PRESSING ENTER.

It is not necessary to press enter if you have not made any changes, In- stead, you may press menu to move you back to the setup menu without making any changes.

Note that these adjustments apply only to the main (home theater) path. Neither of these settings has any effect on either the remote or the record signal paths.

Proper setup and calibration of your new system is essential to its performance. There are several items which should be checked before making the various sys- tem adjustments.

You must be certain of having the proper phasing throughout the system before level calibration can be established accurately and reliably. Accurate phasing of the loudspeakers in the system is also essential for precise localization of images and deep bass response. Ensuring proper phasing is made more complicated than it might seem at first glance if amplifiers of different types are used in the system, since some amplifier designs invert the phase of their output relative to their in- put. Speakers attached to these amplifiers must be connected so that their phase is inverted again to get it back where it belongs.

The simplest way to ensure proper phasing in your home theater is to use only non-inverting amplifiers (such as Proceed® and Mark Levinson® power amplifiers) throughout the system and be extremely careful while making all amplifier/ speaker connections. If this approach is not practical, or if you have lingering doubts about the relative phase of your loudspeakers, compare each speaker to a single speaker which will be used as the reference. We will use the Left front speaker as the reference in our example.

•Relative Subwoofer Phasing: if multiple subwoofers are used, it is important to have their phase with regard to each other correct. Reverse the polarity of one of the two subwoofers while program material with deep bass is playing (being careful not to momen- tarily short the two speaker leads to one another). The slow low frequency sweep “rattle test” on Lucasfilm’s WOW! laserdisc (Chap- ter 16) can be used for this purpose, or any of the below-80 Hz warble tones on the Stereophile Test CD. You will immediately no- tice either a loss or an increase in bass. The correct polarity is the one which exhibits the most bass.

•L–R Phasing: check Left-Right phasing by listening to mono pink noise (such as the pink noise on Chapter 6 of WOW! or Track 4 on the Stereophile Test CD) in the surround off mode. Listen for a solid, stable center image. If in doubt, reverse the leads on the Right speaker only and compare the results. Out-of-phase speakers will

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